Refer to figure.
Windshear could be defined as an abrupt and localized change of wind velocity, that is strength, direction or both. It can occur both vertically and horizontally.

There can be several causes of low-level wind shear:

• The passage of the front in which the isobars change direction;
• A marked temperature inversion;
• Topography and large buildings;
• Surface friction; and
• Cumulonimbus clouds, and their associated weather of heavy rain and hail, can give rise to the phenomenon known as Microburst.

A microburst is generally accepted to be about 4-5 kilometers across and only lasts for a few minutes (around 5 minutes). Although gusts and wind shear can be encountered up to 20 miles from the thunderstorm the downdrafts generated can be very strong up to 6000 ft/min and can often exceed the rate of climb of many aircraft.

Encountering wind shear from a microburst during takeoff can lead to a sudden decrease in airspeed and loss of lift, causing the aircraft to rapidly lose altitude and potentially impact the ground. To recover from such an event, pilots are trained to follow specific procedures:

1. Apply Maximum Power: In response to a microburst encounter, the pilot should apply the maximum available power on the aircraft's engines. This action is necessary to counteract the sudden loss of lift caused by the downward wind shear.

2. Maintain present aircraft configuration.

3. Climb with Best Climb Rate Speed: Maintaining the best rate climb speed is crucial during a microburst encounter. Best climb speed refers to the airspeed that provides the most efficient rate of climb for the helicopter. This speed allows the helicopter to maintain the best lift-to-drag ratio, which is essential for maximizing the climb performance and overcoming the downdraft caused by the microburst.

By applying maximum power and maintaining best climb speed, the pilot aims to minimize the impact of the microburst's downward force and regain altitude as quickly as possible. The combination of maximum power and best climb speed provides the best chance of recovering from the severe wind shear caused by the microburst and ensuring the safety of the aircraft and its occupants.